Most of the models used in the previous chapters were essentially stick figures constructed of dots and lines. When such objects are viewed in three dimensions, it is possible to see the lines on the back side, as if the objects were transparent. This chapter is concerned with removing the lines, which would normally be hidden, from objects so they appear solid.
This chapter will cover two types of situations. The first is called intra-object hidden line removal. This refers to removing hidden lines from a single object. We assume that most objects are constructed of flat planes; the examples ...